Form and Therapy provides a new account of the practical purpose and corresponding limits of Kant’s moral philosophy. I argue that the practical purpose of Kant’s Categorical Imperative is not to supply a test or decision-procedure for the derivation of concrete duties, but to provide the resources for a therapeutic way of reflecting. This therapeutic reflection makes explicit the true form of practical judgment that has been obscured by opposing inclinations. Getting clear about the practical purpose of Kant’s moral philosophy opens up a new way of critically engaging with Kant’s ethics: it allows us to see it as more coherent from the early Groundwork up to the late Metaphysics of Morals, to dispense with some spurious objections to Kant’s ethics, and also to better understand the challenge of ‘formalism’ in Kant’s moral philosophy.